Centrifugal blower wheel structure



7 July 14, 1959 E. LUNDE ETAL CENTRIFUGAL BLOWER WHEEL STRUCTURE 3Sheets-Sheet 1 Filed April 15, 1955 INVENTORS E INAR LUNDE WILL/AM 7fNICHOLS BY Mu v W ATTORNEYS July 14, 1959 E. LUNDE ET AL 2,894,681

CENTRIFUGAL BLOWER WHEEL STRUCTURE Filed April 15, 1955 3 Sheets5heet 2INVENTORS E/NAR LUNDE WILLIAM 1: NICHOLS BY, v.

ATTORNEYS July 14, 1959 E. LUNDE ET AL 2,394,681

CENTRIFUGAL BLOWER WHEEL" STRUCTURE Filed April 15, 1955 5 Sheets-$heet3 Fig.10.

Fig.11.

INV EN TORS EINAR LUNDE WILLIAM 7T NICHOLS BY V2 I ATTORNEYS UnitedStates Patent 2,894,681 CENTRIFUGAL BLOWER WHE'EL STRUCTURE Einar Lundeand William T. Nichols, La Crosse, Wis., assignors to The Trane Company,La Crosse, Wis.

Application April 15, 1955, Serial No. 501,484 3 Claims. (Cl. 230- 134)This invention relates to improvements in centrifugal blower wheels andmore particularly to an improved arrangement for assembling thecylindrical body structure of a blower wheel to an associated hub plate.

Heretofore in the manufacture of centrifugual blower wheels, the processof assembling the large number of parts required for the complete wheelhas been a time consuming and expensive operation. The blade structureof this invention is such that the fan blades are assembled into aunitary flexible strip by the machine which forms the blades. By reasonof this construction, the number of parts required for a complete wheelis reduced and the assembly of the wheel is simplified.

It is an object of this invention to provide a blade structure by whichthe blades are interlocked into a unitary flexible strip.

It is another object of the invention to provide a blade structure bywhich flanges on the blades form rim portions of the wheel.

It is another object to provide a blower wheel which has a maximumeffective blade length with only a relatively small space at the endsfor blade retention.

It is still another object of the invention to provide a centrifugalblower wheel in which the parts thereof can be assembled very rapidly sothat the wheels can be manufactured in quantities with low cost forlabor and material.

Other objects and advantages of the invention will become apparent asthe specification proceeds to describe the invention with reference tothe accompanying drawings in which:

Figure 1 is a sectional view of the blower wheel taken on line 11 ofFigure 4;

Figure 2 is a perspective view of a portion of the blower wheel showingthe blade structure;

Figure 3 is a perspective view of a part of the hub plate of a doublewidth blower wheel;

Figure 4 is a sectional view taken on line 44 of Figure 1;

Figure 5 is a sectional view of the end of a blade taken on line 55 ofFigure 6.

Figure 6 is an elevational end view of a blade.

Figure 7 is a sectional view of part of the hub plate of a double widthwheel taken on a radial plane.

Figure 8 is a partial sectional view of a double Width wheel taken on aradial plane.

Figure 9 is an elevational view of part of a wheel showing the weldssecuring the blades together.

Figure 10 is an elevational view of part of a wheel showing amodification of the invention in which the blades are spot welded toeach other.

Figure 11 is an elevational view of part of a wheel showing anothermodification of the invention in which the blades are seam welded toeach other.

Referring now to the drawings and particularly Figures 1 and 2, numeral10 designates a hub plate to which is secured a hub 12 and blades 14.The blade 14 has a vane portion 16 which is curved in cross-section anda flange base portion 18 at each end extending at rig t angles to thevane portion 16. Extending from the flange base portions 18 are flangeend portions 20 ofiset out wardly from the flange base portions 18 sothat the flange end portions 20 will receive therebetween the flangebase portions 18 of the next adjacent blade.

The flange base portion 18 of each blade has an inwardly extendingdimple 22 having its center substantially at the axis of curvature ofthe convex surface of the vane portion 16 of the blade. The flange endportion 20 of each blade has an inwardly extending dimple 24 whichengages in the dimple 22 in the flange base portion of the next adjacentblade to hold the blades in the form of a flexible strip leaving theblade forming press. The dimple 24 may be formed prior to the assemblyof the blade to the next adjacent blade. The resiliency of the flangeportions 18 and 20 will permit the blade to be nested on the nextadjacent blade and the dimple 24 will snap into place in the dimple 22.Alternatively the press can assemble the blade in nested position on thenext adjacent blade and form the dimple 24 into the dimple 22.

A strip having the required number of blades 14 for a given wheel isthen removed from the continuous strip produced by the press. Afterremoval this strip is held in annular form and the first blade is nestedin the last blade with the dimples of the blades in engagement. Theblades 14 are then secured to each other by welding. Various forms ofwelding may be used.

Figure 9 shows a brazing weld which is produced by placing brazingmaterial in contact with the flange portions 18 and 20 of the blade andthen heating the blade the flange end portion of each blade iselectrically spot welded at 26 to the flange base portion of theadjacent blade.

Still another form of weld is shown in Figure 11 in which a seam weld 28is produced between the flanges of the blades by an electric or gaswelding process.

The hub plate 10 has a hub 12 secured thereto in any suitable manner asby swaging the flange 30 against the hub plate 10. The hub plate 10 hasa peripheral channel 32 which receives one end of the blade assembly asshown in Figure 4.

The hub plate 10 is then secured to the blade assembly by welding orriveting at the peripheral channel 32. We prefer to electrically spotweld the blade assembly to the hub plate at several spaced points. Ifdesired the brazing procedure described with reference to Figure 9 canbe used to simultaneously braze the hub plate 10 and the assembledblades into a unitary structure.

As shown in Figure 8 a double width blower wheel comprises a hub plate34 with a blade assembly secured to each side of the hub plate at theperiphery. Hub plate 34 has a hub 36 secured thereto in any suitablemanner as by swaging the flange 38 against the hub plate 34. The hubplate 34 has peripheral flanges 40 extending at right angles from thehub side of the hub plate and peripheral flanges 42 extending at rightangles from the other side of the hub plate. Hub plate 34 has aplurality of projections 44 extending from one side and a plurality ofprojections 46 extending from the other side. One blade assembly ispositioned and supported by flanges 40 and projections 44, the otherblade assembly is posi tioned and supported by flanges 42 andprojections 46. The blade assemblies are secured to the hub plate 34 bywelding or riveting. We prefer to electrically spot weld the bladeassemblies to the hub plate 34 at several spaced points. If desired, thebrazing procedure de- Patented July 14, 1959 scribed with reference toFigure 9 can be used to simultaneously braze the hub plate and theassembled blades on both sides of the hub plate into a unitarystructure.

While we have described the foregoing preferred embodiments of ourinvention, we contemplate that many changes may be made withoutdeparting from the scope or spirit of our invention and we desire to belimited only by the claims.

We claim:

1. An assembly for incorporation in a centrifugal blower wheelcomprising a plurality of blades, each of said blades having a vaneportion and flanges extending from each end of the vane portion andlying in planes which are substantially at right angles to said vaneportion, each of said flanges having a base portion and an outwardlyoflset end portion, said base portions and said outwardly offset endportions having substantially circular indentations, the outwardlyofl'set end portions of the flanges of a blade receiving therebetweenthe base portions of the flanges of the next adjacent blade, with thesubstantially circular indentations of the end portions extending intothe substantially circular indentations of the base portions.

2. In a centrifugal blower wheel the combination of a plurality ofelongated blades, each of said blades having a vane portion of curvedcross-section and flanges extending from each end of the vane portionand lying in planes Which are substantially at right angles to said vaneportion, each of said flanges having a base portion, an outwardly offsetend portion, and a shoulder portion between said base portion and saidend portion, said shoulder portion having a curvature substantially thesame as the curvature of said vane portion, said outwardly offset endportions of the flanges of a blade receiving therebetween the baseportions of the flanges of the next blade, the base portions and the endportions of said flanges having nesting substantially circularindentations connecting said base portions of the flanges of one bladewith the end portions of the flanges of the next blade and a continuousannular welding bead welded to said flanges at their outwardly facingsides.

3. An assembly for incorporation in a centrifugal blower Wheelcomprising a plurality of elongated blades, each of said blades having avane portion of curved cross section and flanges extending from each endof the vane portion and lying in planes which are substantially at rightangles to said vane portion, each of said flanges having a base portion,an outwardly offset end portion, and a shoulder portion between saidbase portion and said end portion, said shoulder portion having acurvature substantially the same as the curvature of said vane portion,said outwardly oflset end portions of the flanges of a blade receivingtherebetween the base portions of the flanges of the next blade, thebase portions and the outwardly offset end portions of said flangeshaving nesting substantially circular indentations and providing a meanspivotally connecting said base portions of the flanges of one blade withthe outwardly offset end portions of the flanges of the next blade.

References Cited in the file of this patent UNITED STATES PATENTS1,029,554 Neumayer June 11, 1912 1,745,854 Lawaczeck Feb. 4, 19302,044,028 Szekely June 16, 1936 2,231,062 Evans Feb. 11, 1941 2,258,231Evans Oct. 7, 1941 2,336,231 Dodge Dec. 7, 1943 2,392,113 Anderson Jan.1, 1946 2,458,041 Wessel Jan. 4, 1949 2,592,851 Beranek Apr. 15, 19522,632,397 Jandasek Mar. 24, 1953 2,711,285 Burrowes June 21, 19552,724,547 Abbott et a1 Nov. 22, 1955 FOREIGN PATENTS 12,347 GreatBritain of 1901 759,514 Germany Apr. 9, 1953

